Uncategorized
  • Axial Interstitium:
    • Surrounds and supports the bronchovascular bundles.
    • Includes connective tissue along the bronchi, pulmonary arteries, and veins.
    • Extends from the hilum to the periphery of the lung.
  • Parenchymal (Acinar) Interstitium:
    • Found within the alveolar walls.
    • Includes the fine network of connective tissue that surrounds capillaries and provides structural support to alveoli.
    • This component is crucial for gas exchange and is the primary site affected in interstitial lung diseases.
  • Peripheral (Subpleural) Interstitium:
    • Located at the outermost layer of the lungs.
    • Lies beneath the pleura and extends into the septa between lung lobules.
    • Includes the interlobular septa and lymphatic vessels.

Axial Interstitium with Associated Lymphatics

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 The Lymphatics in the Axial Interstitium Centered Around the Bronchovascular Bundle
The axial interstitium of the lungs that includes the lymphatics (overlaid in yellow) contain the connective tissue elements that extend from the hilum to the periphery of the lung.
Ashley Davidoff MD TheCommonVein.net
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Pulmonary Artery and
Airway
Tubular Components of the
Bronchovascular Bundle

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 BRONCHOVASCULAR BUNDLE
Ashley Davidoff MD TheCommonVein.net 0828030040b01

Lymphatics in the Bronchovascular Bundles Involved in LIP
Extending to the Small Airways

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 LIP Lower Lobe Predominance Along the Bronchovascular Bundles
3D reconstruction of a CT scan shows the position of the lymphatic involvement of cellular infiltration along the bronchovascular bundle to the lower lobes
Ashley Davidoff MD TheCommonVein.net
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Lymphatics in the Parenchymal Interstitium
Secondary Lobules
Extending to the
Interalveolar Septa
Interlobular Septa
Subpleural Layer

Parenchymal (Acinar) Interstitium:

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 The Superficial and Deep Lymphatic Systems at the Secondary Lobular Level
The diagram shows the 2 systems of lymphatic drainage at the level of the secondary lobule.  The superficial system drains some of the interstitium of the secondary lobule, runs in the interlobular septa and drains all the pleura.  Thee pathway to the lymph nodes in the mediastinum is via the pulmonary veins.  The deeper system drains the interstitium in the interalveolar septa, and then they travel along the bronchovascular bundle accompanying the bronchi and pulmonary artery and into the lymph nodes of the hila and mediastinum
Ashley Davidoff MD TheCommonVein.net lungs-0767

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 The Superficial and Deep Lymphatic Systems at the Secondary Lobular Level
The diagram shows the 2 systems of lymphatic drainage at the level of the secondary lobule.  The superficial system drains some of the interstitium of the secondary lobule, runs in the interlobular septa and drains all the pleura.  Thee pathway to the lymph nodes in the mediastinum is via the pulmonary veins.  The deeper system drains the interstitium in the interalveolar septa, and then they travel along the bronchovascular bundle accompanying the bronchi and pulmonary artery and into the lymph nodes of the hila and mediastinum
Ashley Davidoff MD TheCommonVein.net lungs-0768

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 This image is a panoramic view of the lung showing in this case almost rectangular secondary lobules surrounded by interlobular septa (cream borders) The distal bronchioles (teal) and pulmonary arteriole (royal blue are shown in the centre of a lobule in the right lower corner. The branches of these two structures are shown in the secondary lobule with the acinar airways shown in teal and the presumed course artistically inferred in royal blue. Within the interlobular septa (light pink) remnants of the pulmonary venules (red – inferred) and lymphatics (yellow inferred) course going in the opposite direction to the arteriole and the airways. Courtesy Armando Fraire MD. code lung pulmonary alveoli alveolus secondary lobule interlobular septa vein lymphatic histology interstitium interstitial normal copyright 2009 all rights reserved

Courtesy of: Armando Fraire, M.D. Ashley Davidoff TheCommonVein.net

Lymphatics in the Interlobular Septa

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 Secondary Lobule
The top image (a) shows an anatomic drawing of a secondary lobule of the lung subtended by a lobular bronchiole (lb) and arteriole (pa). The interlobular septum contains the venule (red) lymphatic (yellow) and septum (maroon)
The anatomical specimen of the lung (b) shows normal intralobular parenchyma while image c shows the centrilobular arteriole (navy blue) and centrilobular bronchiole (teal) and interlobular venule (red) and lymphatics (yellow) The interlobular septum is slightly thickened
Ashley Davidoff TheCommonVein.net

Infiltration of
Lymhocytes Histiocytes and Plasma Cells into the
Interalveolar Septa

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 LIP Lower Lobe Predominance Along the Bronchovascular Bundles
3D reconstruction of a CT scan shows the position of the lymphatic involvement of cellular infiltration along the bronchovascular bundle to the lower lobes
Ashley Davidoff MD TheCommonVein.net
32645a06b lymphatics
32645a06L01 lymphatic

lungs-0785-lo-res-secondary-lobule-272x300.jpg

 Secondary Lobule
The top image (a) shows an anatomic drawing of a secondary lobule of the lung subtended by a lobular bronchiole (lb) and arteriole (pa). The interlobular septum contains the venule (red) lymphatic (yellow) and septum (maroon)
The anatomical specimen of the lung (b) shows normal intralobular parenchyma while image c shows the centrilobular arteriole (navy blue) and centrilobular bronchiole (teal) and interlobular venule (red) and lymphatics (yellow) The interlobular septum is slightly thickened
Ashley Davidoff TheCommonVein.net

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 Secondary Lobule – Lymphatics and Venules Travelling Together
The arteries and airways pair up and travel together from the interlobular septa to the hilum.   The pulmonary lobule, also called the secondary lobule is a structural unit surrounded by a membrane of connective tissue, and it is smaller than a subsegment of lung but larger than an acinus. This diagram shows two secondary lobules lying side by side. The pulmonary arteriole (royal blue) and bronchiole (pink) are shown together in the centre of the lobule (“centrilobular”), while the oxygenated pulmonary venules (red) and lymphatics (yellow) are peripheral and also form a formidable and almost inseparable pair.
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Ashley Davidoff MD
TheCommonVein.net

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 Anthracotic Lung
Anthracosis – Note the accumulation of carbon particles within the lymphatics along the interlobular septa, outlining the secondary lobules. The carbon particles are inhaled from an anthracotic urban environment. Courtesy Ashley Davidoff MD. 32291 code lung interlobular septum septa secondary lobule pulmonary lobule intertstitium interstitial gross pathology carbon

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 Infiltration of Lymphocytes Plasma Cells and Histiocystes into the walls of the Bronchioles and Small Airways
Artistic rendering shows a normal bronchiole (a) with early infiltration into the wall of the airway, (b) withprogressive infiltration with luminal compromise (c) evolving into obliteration (d). This would result in centrilobular nodules radiologically. Subsequently there is necrosis and a thin walled cyst remains
Ashley Davidoff MD TheCommonVein.net  139264.lungs

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 LIP Sjogren’s Syndrome and Amyloidosis
58 year old female with known Sjogren’s syndrome presents for CT evaluation of the chest.  Artistic rendition of her CT in the coronal plane shows multiple thin walled cysts in close association with bronchovascular bundles involving the lower and mid lung fields. Biopsy confirmed the associated presence of amyloidosis and LIP (lymphocytic interstitial pneumonia) 
Ashley Davidoff MD TheCommonVein.net  139263-02Lb01

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 Lung Cysts of LIP
The cysts of LIP (lymphocytic interstitial pneumonitis) are characteristically associated with the bronchovascular bundle (arteriole dark blue, bronchiole teal).
Ashley Davidoff MD TheCommonVein.net  139265.lungs

Peripheral (Subpleural) Interstitium

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 The Superficial and Deep Lymphatic Systems at the Secondary Lobular Level
The diagram shows the 2 systems of lymphatic drainage at the level of the secondary lobule.  The superficial system drains some of the interstitium of the secondary lobule, runs in the interlobular septa and drains all the pleura.  Thee pathway to the lymph nodes in the mediastinum is via the pulmonary veins.  The deeper system drains the interstitium in the interalveolar septa, and then they travel along the bronchovascular bundle accompanying the bronchi and pulmonary artery and into the lymph nodes of the hila and mediastinum The subpleural interstitium is rich in lymphatics 
Ashley Davidoff MD TheCommonVein.net lungs-0768

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 Ill Defined Centrilobular Nodules and Subpleural Nodules
The infiltration of lymphocytes, histiocytes and plasma cells along the lymphatics of the lungs, can sometimes result in ill defined nodules that may be centrilobular or subpleural in location
Ashley Davidoff MD TheCommonVein.net
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